Printing telegraph system



June2,1942. 4mm" 2,285,265

PRINTING TELEGRAPH SYSTEM I Filed Dec. 28, 1940 5 Sheets-Sheet 2lllllllllllli ATTORNEY June 2,1942. .c J, F|TH 2,285,265

- PRINTING TELEGRAPH SYSTEM Filed Dec. 28, 1940 5 Sheets-Sheet sATTORNEY u 2,1 4 c. 4. m f 28 265 I PRINTING TELEGRAPH SYSTEM n iieaDec. .28, 1940 5 Sheets-Sheet 4' ATTORNEY June Z, 1942. c, J. FI CH-2,285,265

I PRINTING TELEGRAPH SYSTEM Filed D80. 28, 1940 5 Sheets-Sheet 5 STM SRMmeg/yr v 's-.10., yy

Jammy another Patented June 2,

,uu rso is'ra'lEs ear -2N messes r OFFICE rams mo ransom srs'rauClyde 1. 'Fitch, Endwell, N. I, assignor'to Intional Business Machin NewYork, N. 2.,

es Corporation,

a corporation of New York s ueeueii December 20,1940, Serial No. 312.111

' s lotus-as) The invention relates to a printing telegraph system orthe start-stop type, and more particularly to such systems adapted fortwo-way communication.

The present application is based on the unidi-' rectional systemdisclosed in the co-pending application Serial No. 370,675, filed Dec.18, 1940.

.In the said co-pending application, the code groups oi. impulses aregenerated electronically under control of an impulsedistributingmeans,which is actuated, step-by-step, a predetermined number of times,during, each signaling cycle. oscillatory means are provided foreffecting energization oi. the actuating means of the impulsedistributing means, and for controlling the. conductivity of theelectronic discharge devices/employed for generating the impulses. Eachtransmitting and receiving station is provided with just mentioned. Atthe transmitting station, upon each operation of the control switches,

. the impulse generating and distributing meansthe oscillatory means andimpulse distributing means are set into operation, for the duration of asignaling cycle, to generate code groups 01' impulsesyduring the cycle,in accordance with the settings of,the control switches. The generatedimpulses are eii'ectlve to control suitable v signal transmitting'means,the initiated signals of which, in turn are eflective to set into opereation, each signaling cycle, these oscillatory means and impulsedistributing means atthe receiving station for controlling theenergization Therefore. an obiect oi the present invention resides inthe provision of a start-stop printing telegraph system employingoscillatory control means for controlling the actuation oi thedistributormeans each signaling cycle, and wherein the signal initiatingmeans can be conditionedto be effective to transmit code groups ofsignals under control ofthe'distributor means with the 1 oscillatorymeans set ior operation at'a certain frequency rate, and the signalreceiving means can be conditioned to be efiective to be responsive tocode groups of signals under control or the said distributor means withthe oscillatory means 1 set for operation I at a difierent frequencyrate without affecting the-said setting for obtaining thetransmittingfrequency rate.

Other objects of the invention will be pointed out in the followingdescription and claims and illustrated in the accompanying drawings,which.

disclose, by way 0! example, the principle or the invention and the bestmode, whichhas been contemplated, of applying that principle. i

In the drawings:

Fig. 1 is a wiring diagram showing the circuit 7 connections of thecontrol elements of a preferred type of unidirectional. system.

liig. 2 is a right end view of the distributing means.

of the control magnets thereat inaccordance I with the character signalsreceived.

- In the present application, each station is pro- I vided with a singleimpulsedistributing means, associated oscillatory control means andimpulse generating means. A send-received switch pro vided at eachstation conditions the various control circuits so that the system iscapable of initiating and sending code groups of signals with the switchin one setting, and receive the signals and print the characters withthe said switch in setting. Provision is also made, whereby thefrequency 0! the oscillations generrig. a ie-e left end viewer thedistributing I means. s

Pig. 4 is a sectional view taken along the lines 'clutchunit assembly.

Fig. 9 is an exploded view or the assembly shown'in Fig. 8.

Fig. 9a is a detail view oi the dog litting lever oithe clutch unit.

ated for transmittingpurposesmay --be diiierent from the frequency ofthe generated oscillations when the system is employed for receivingpur-.

poses. The adjustments for controlling the different frequency rates,are undisturbed when switching from sending,to receiving, and viceversa. With the provision of this i'eature, communication betweendiflerentstations is simplified, particularly when the irequency ratesfor the different stations vary in each instance,

Fig. 10' is a wiring diagram showing the circuit connections of thecontrol elementszfor a preferred type oi two-way signaling system.

j i a General description The printing telegraph system to bedescribedis oi the start-stoptype, wherein a continuous signal or currentcondition is. impressed upon the transmission medium at the timescharacter signals are not impressed thereupon. v Referring now to Fig.1, at the transmitting section as described in U. 3, Patent Nos.1,214,515 and 2,161,564, or as is well known, may be positioned trolledby the devices referred to. in said patents, as for example, the storagerelays described in the latter patent. 7

An oscillatory means, in the form of an electronic oscillator TI, isprovided for controlling the alternate energization of the impulsedistributing means actuating magnets 25 and 26, a predetermined numberof times, each signaling cycle. An impulse generating device T3 is alsoprovided, and arranged so that the conductivity of the triode sectionsthereof are controlled by the oscillatory means, in synchronism with thealternate energization of'the control magnets 25 and 25. Thus, duringthe signaling cycle, when the impulse distributing means are releasedand actuated, upon operation of the control contacts. timed impulses aregenerated by the device T3, in accordance with the contact settings tocontrol the signal generator (571 accordingly.

At the receiving station, impulse distributing means, oscillatorycontrol means and impulse generating means similar to those of thetransmitting station are provided. The control magnets Nil-M6 of asuitable teleprinter means 36. such as described in U. S. PatentsNos.128,422

ease,

under control of suitable storage relays conand 2,1652%7, are connectedto the stationary brushes of the impulse distributing means, so that thesaid magnets are energized in different combinations corresponding tothe character signals transmitted for enacting recording of thecorresponding characters.

With reference to Fig. 10. a send-receive switch S is'provided at eachstation to condition the associated control circuits so that uponsetting the switch, in one status. the contacts CI- CG, and CS areeffective to control the distributor means and oscillatory control meansto initiate the code groups of signals, and, in another status, themagnets MlM6, and MP are rendered effective to be responsive to the codegroups of signals which are impressed thereupon under control of thesaid distributor and oscillatory means; A pair of variable capacitormeans TVC and RVC are provided for controlling the frequency rates ofthe oscillations generated by the said oscillator for signaltransmitting and receiving purposes, respectively. Upon altering thestatus of the switch S, it will be shown that the setting of eachcapacitor means remains undisturbed, thereby'slmplifying thetransmitting and receiving operations at the different stations.

Before describing the specific operations of the system, the individualcontrol units and the unidirectional signaling system will be describedflrst. The impulse distributing means will now be explained. in detail.

Impulse distributing means mounted in the supporting frame 2i andurgedby springs 22 to the normal positions shown.

, Attached to the said arms are the armatures 23 and 24 of actuatingmagnets 25 and 2t, respectively, the latter being suitably mounted onthe said supporting" frame.

The spacing of the ratchet teeth I8 and the shapes thereof, and thestrokes of the actuating pawls it and H are such that alternateoperation of the pawls is necessary to advance the ratchet l5 and shaft9 step-by-step. For example, with the described elements in the homeposition as shown, the stroke of pawl i7 is insuflicient to advance theratchet one step, therefore, it is understood, that energization ofmagnet 26 at this particular time is inefiective to advance the ratchet.However, energization of magnet 25 is effective, at this time, to causeadvancement of the ratchet one step, by attracting its armature 23, andellecting a partial clockwise rotation of arm it, thereby urging thespring urged pawl l8 upwardly to engage one of the ratchet teeth. Theadvancement just eilected is sumcient to position one of the ratchetteeth in the path of the pawl it, whenever the related magnet 28 isenergized. Until the latter magnet is energized, additionalenergizations of magnet 2d are ineffective tocause further advancementof the ratchet. v

Attention should also be directed to the fact, that the ratchet teethare shaped, so that when one of the magnets is energized to attract itsrelated armature and effect partial rotation of the associated arm, thefree end 2'? of the said arm '(at the end of its stroke) engagesdirectly one Each of the conducting rings It and H are secured onindividual insulating collars 28, which collars are suitably secured tothe shaft 9. One of the collars is hollowed at one end to receive theconducting ring l2, which ring as well as ring I3. is secured to theshaft 2 in conductive relationship thereto. The conducting ring I2 isprovided with four radially extending conducting segments l2a-l2d. Fourequally spaced conducting segments low-ltd and lla-lld, which areintegrally formed extensions of the conducting rings l0 and M,respectively, are provided to extend across the periphery of the relatedinsulating collar as shown. Two groups of arcuately arranged conductingbrushes. namely. Bl, B3, B5, BP,BS, B03, and 32,34, B6,

BCI, BC2, are provided, and are supported by Referring now to Figs. 2 to4, the impulse disthe path of the conducting segments Ila-4 Id,

Two spring engage continuously the conducting segments BC! is positionedto engage continuously the conducting ring'ii; brushes B2, Bl, B8 arepositioned to extend inthe path of the conducting segments Illa-Hid,brush BCfis positioned to I the conducting ring l0, and brush BCI ispositioned to engage continuously the conducting ring ll. e

As mentioned, upon alternate energization of the magnets. "and 28, thesaid conducting rings andassociated segments are advanced, fromthe2,285,365 a brush as i positioned to extend in the path er Ila-42d, andbrush means will now described. I g oscillatory control means forimpulse distribut'-* ing means Referring now toFig. 1, one ofoscillatorycontrol means is shown discharge device Tl,

- connected to'one terminal of the primary winding home position shown,to engage different ones of the associated conducting brushes. of theadvanced rings and segments, is to a distance equal equivalent to halfthe distances sepa- *rating the conducting tips of the equally spacedbrushes BP,-'Bi, 83,35 andBl Bl, BB, The width of each of .theconducting segments Illa-Jld'and' iia-l ld is approximately equivalenttoone half the distances separating the conducting tips of the lattermentioned brushes. Thejwidth of each of the conducting segments Ila-I211is approximately half of the width of one of the segments.iiiallld orIla-lid. Dure ing'eightsuccessive steps'of-advancement of the said ringsand segments, acomplete cycle of operation of the associated brushes iseffected.

Each step,

ii of transformer 32, the other terminal of which is connected byconductor 33 to the terminal I of a suitable power supply. The circuitconnected to'the grid "includes the resistor 38 and' the secondarywinding 3'! of the transformer 32. The latter winding has anintermediate connectionfrom point 38,- by conductor 39,; to terminal 40of the said power supply. One terminal of.-

the secondary winding is connected to resistor M, which in turn isconnected,

L triode' type. An adjustable capacitance A! and.

At the home position shown in Figs. 2 m4, and

diagrammatically indicated in Figs. 1 and 10, the

brush BS enga es the conducting segment I21), 1

brush BP engages the conducting segment Ila.

. Motor 54 to 'brush BCl.

of device T2 are connected Since brushes BC], 302, and BC! engage COB-rtinuously' the related conductingrings no reference will be made tothese brushes during the following analyzation.

Upon completion of the first step, the contact between segment Ila andbrush BP is broken.

the contact between segment Rb and brush BS is broken, and contact ismade between conducting segment Nb and brush Bi. Upon the second step.the segment lib remains in contact with brush Bl, andcontact is madebetween segment I lib. and brush B2:- the .third step. the contactbetween segment ilb and brush BI is broken,

and contact is made between thesaid segment v and brush B3, the segmentNib remains in contact with brush B2: fourth step. the.contact'be-.

tween segment Hlb and brush B2 is br'oken..-and

' contact is made between thisisegment and brush B4, the segment libremains in contact with brush B3; fifth step, Ii b andbrush B3 isbetween this segment and brush B5. the segment illb remains in. contactwith brush Bl: sixth step,- the contact between segment I b and brush B4is broken. and contactis made between this segment and brush BB, thesegmentzllb remains in contact with brush B5; seventh step. the contactbetween segment H1) and brush B5 is broken; and contact is made betweenthis segment and brush 13?. the segment illb remains in contact withbrush-B65 eighth step. the contact between segment liib'and brush B6 isbroken, contact is made between segment I and brush BS, and the see-.ment I lb remains in contact with brush BP; The

conducting rings and segments and the related brushes BC! and B03,

a-nd a'node elements of v 1 the conventional connections for causing thedethe contact between segment broken. and contact'is made brushes arenow in a home position, similar to the one indicated in the figures.

The purpose of the describedarrangementof brush connections, during onecycle of operation of the impulse distributing means, will be explainedduring the description of the circuit diagram in Fig. 1. The oscillatorymeans for 'resistors and 46 at the The grid 52 of device Tlis connected,by conresistance Ii are connected in shunt relationship with thesecondary winding 31. 'The cathode elements of devices TiT3are-connected, by conductor 41, to the terminal 48 of the power supply..The circuit connected to grid 48 0!. de vice T2, includes resistor 50,and h point indicated 5i;-

ductor 53, to grid of device TI. and by con-,

to the actuating mag-- nets 2! and 26 respectively, whereasythe anodes51 and "of device -T3 respectively.

The circuit connections of'the grid, cathode device Ti described arevice TI to operate as an electron oscillator. The

frequency of the generated oscillations can. be determined by theadjustable capacitance 4!, or if desired the magnetic gap of 32 maybemadelvariable and adjustable, as indicated by the dotted arrow. Anadditional con circuit can be traced from terminal 34 of the power.supply to. conductor .59,- normally trol closed contacts CS. resistance80; brush BS, segmenti2b, conducting rings "[2 and I3. brush.

'BCI. conductors '54 and "(grids 35 and 52 of and respectively.resistance -36, secondary winding 31, conductor 3!, terminal resistance6| to terminal 48 devices Ti of the power suppl of. the power supply.

Whenever. the circuit just traced 35 and 52, due tothe connection fromthe-said grids to terminal of the power supply.' Howe evenwhen the saidtraced circuit is connected to" the grids l5 and 52, the voltage dropacross resistance, is effective toneutr'alizethe said bias-1 ingpotential'referred to. thereby'placing the grids 3i and 521stsubstantially zero biasing potential.

The values of resistances-30' and are determined andchosen. across theiormeris suihcient to' neiitralize the biasing potential impressed bythe circuit from terminal 40 of the power supply. to grids as and llnderthe last mentioned conditions, the device TI is conductive; causing aconstant current M in. the circuitfrom terminal "o the power supply.-the-primary winding ll, anode element '30 the related cathode element,conductor 41 to'ter minal ll of the said power supply, to establish tocomprise the electron the anode 30 of' which -is.-'

by conductorlLto grids l3 and 44 of-the electron discharge devices. 1

V T2 and T3, respectively, which are-of the twin is connected .to 4

.The anodes and B6;

are, connected to the the transformer V is open} a biasing potential isimpressed upon the said grids so that the said voltage drop.

, 'At this predetermined and constant magnetic field around thetransformer 82, thereby placing the circuits connected to the avnon-oscillating condition.

Now, whenever the positive :,,,,anaei from terminal 33 is removed iromthe grid 3!, for ex-- ample, by opening the contacts C8, theneutralizing voltage drop across resistance is removed, and thebiasing-potential impressed upon the said grid instantly is changed.lrom zero to a negative value, thus rendering the device Tlnon-conductive momentarily, and thereby cutting on the flow of'currentthrough windingpSL-and causing thesaid magnetic ileld of transformer 82to collapse.

' moment, a voltage is induced across winding 31 whlch'tends to renderthe grid more negative with respect to its cathode, and causes thecondenser 85 to be ,Iully' charged. Upon discharge of the said condenserthe grid 35 becomes positive, with respect to the cathode, to render thedevice conductive momentarily to energize the winding 3 i. In this wellknown manner, oscillations of a frequency determined by the chosen C andL values of the said capacitance and in ductance are generatedcontinuously while the -positive potential from terminal 36 is not im=pressed upon the grid 35. However, when the said positive potential isimpressed thereupon,

by closing thecontacts CS for example, the generation oi'theoscillations is interrupted. In this in "er, an oscillation generator isprovided,

. which'fcan be started and stopped in the manner described, whereby thegenerated oscillations at thevery start of its operations are virtuallyof maximum amplitude, and upon stopping the opstations of the generatorthe generation of oscillations is stopped instantly. Fig. shows thevoltage wave shapes of the oscillations generated for a chosen cycle ofoperation, namely, four complete oscillator cycles.

it is noted, that the grids 63 and 4c of device T2 are'conneoted inpush-pull relationship to the terminals of winding 31. so that uponoperation of the oscillation generator, the two triode sections ofdevice T2 are rendered conductive alternately. In this manner, theactuating magelements of device '1 in aaaltees tra m ttins unit 68 areshown connected tothe individual hes Bi-BB of the impulse distributiiigmeans, and by a common conductor 85 are connected to the anode-cathodecircuit of electron discharge device 61 and'the brush BP.

It is well irnowmthat the said contacts can be controlled inapermutatlve manner in accordance with the selected character operationsof the transmitting unit. It is equally well known, that the normallyclosed contacts 08 are opened for each permutative setting or operationof the contacts C5-C6.

It was explained in detail, that device Tl nor- I mally is conductivecontinuously, whenever the fill contacts CS are closed, and with theimpulse distributing means positioned in the normal home position shown.q-ridii of device T3 is connected in parallel to grid 35 of device TI,and consequently the triode section controlled thereby is fullyconductive, when the contacts OS are closed and with the saiddistributing means in the said normal position.

For these conditions, a circuit can be traced from terminal d8 of thepower supply to conductor ti, cathode and anode 58 of device T3, brushB03, conducting ring it and segment Ha, brush B? to the cathode elementof device 81. The

electron discharge device 61 is a twin triode type connected as anoscillator, the frequency of which is determined by the C and L valuesof the capacitance Gt and transformer se. The center tap oi the primarywinding of said transformer is connected to terminal 3d of the powersupply, and the terminals of said winding are connected to the anodeelements of device 3?. Each anode is coupled to the opposite grid bymeans of condensers it and H, and the 'grid elements are connected tocathode through the grid leak resistors l2 and it.

nets25 and 28 are energized alternately, in the order mentioned, tooperate the impulse distributing means, by advancing the conductingrings and segments, step by step, for a chosen cycle oi. operations.

,It should be mentioned, that although the grid 49 of device T2 isconnected to the same terminal of winding 31 as grid 350i device Ti thepotential impressed thereupon normally is negative with respect to itscathode, and not of. zero value as in the case of grid 35. Thereason forthis being, that grid 49 is connected to point 5| through a seriesresistor 50. Therefore, the triode sec- 4 'tion of device'TI' controlledby grid 49 is not fully conductive, atthe times when the positivepotential from terminal sl-is'impressed upon grid 35 of device TI, torender thelatter fully conductive. In fact, at-such times, a relativelysmall and negligible: amount. of current flow is present in the circuitconnected to anode 56, so that normallyverylittlecurrent flow passesthrough the winding or magnet 26, and consequently av negligible amountof energy for the latter need be dissipated. r

Transmitting circuit arrangement With reference now to the circuitconnection l shown in the upper half sectionot Fig. "1, the

permutatively controlled contacts (ll-9C8 ot'the From the ioregoingdescription, it should be evident and adequate for the present purposeto state, that, when sumcient potential is applied between the centertap or the primary winding of transformer 69 and the cathode of device67, oscillations of a predetermined frequency are generated, and thatwhen this potential is removed, the generation of said oscillations isinterrupted. The generated carrier oscillations are impressed upon thesignal line terminals It through the volume control device l5.desirable, particularly when utilizing the system for telephone linetransmission purposes, that the signal carrier frequency should be setfor approximately 1800 cycles, and depending upon the desired speed ofoperation, the base frequency of the oscillations generated by device Tican be approximately from 20 to 50 cycles.

Now, so long as the triode section of device T3 controlled by grid 52 isconductive, sufilcient potential is impressed upon the described inputcircuit of device 61 to render the latter operative to generate thesignal oscillations, which in turn,

it has been found 'FigLS. I 4 a Since, current flow, in the circuitconnected tocycle.

and, alternately', to cause the conducting rings of the said conductingrings represent a-complete signaling, cycle, so that the brush BS, atthe end "of :eachseries of eight steps, engages one of the and segmentsto sweep across the'associated brushes. It was also mentioned that eightsteps conducting segments INA-[2d, and thereby impresses theneutralizing potential upon theinput circuit of device Tl, whereuponfurther genera-- tion of oscillations is interrupted -(assuming ofcourse, that during the signaling cycle the contacts CSl-are closedwhichjis the normal practice). It should be stated, at this time, that,it

is assumed, the sections indicated .i, 3,, 5 and I of sections 2, 4, 6,and '8' are eiiective to render the Qgrid-49 positive to cause themagnet 25 to be energized, during the' said cycle. r In order tocomplete the description of the 'tive, thus rendering the oscillatordevice 51 nonconductive, Since contacts C2 are open, no sigpalingcircuit can be completed through brush B2 This condition is indicated atD in Flgl 6.

During the fourth cycle of operation'oi device Tl, contact'is brokenwith brush-B2 and made withbrush B4, but no current passes throughtransmitting circuit arrangement; it-will be explainedi'briefiy, how thepermutation signals are generated, therefore, assume thatthetransmib,

tin U it 65 is operated to close the contacts Cl,

C4 and C5 during the signaling cycle, and that I contacts CS areopenedmomentarily. Normally,

the continuous signal indicatedatA in, Fig. 6

is impressed upon the transmission medium.

Upon opening of the contacts CS, grids 43 and 4& are rendered positive,alternately, due to the operation of device'Tl as explained. Grids 4.4

and 52-, similarly are rendered positive, in. synchronism with grids and49, respectively Therefore, during the first half cycle of oscilla-.time;

tion of device T1, the potential impressed on grid"? 52 drops to below anormal plate current cutoff value, and. the potential impressed onzgrid35 is,

positive to render the related triodesection con- 'of'operation, ,whenthe" coriductingrings are adg s thereby rendering the device ductive;Thus, during the said first halfcycle vanced one step, the oscillatordevice 51- is rendered inoperative, and consequently no sig'naloscillations are impressed upon :the line terminals I4. This conditlonisindicated atB in;

anode '58, is instantly cut off, when contacts'CS are opened, duringtheflrst half cycle of operaftion'when'the conducting rings are advancedone step, there is no current flow through brush BP,

when this contact "is broken. Similarly, when contact ismade with brushBI, even though con- "tact CI is closed, no current fiows throug h thecircuit associated"therewith, at this time in the During theseco'ridhalf cycle of operation 'of -.device Tl, brush Bl remains incontact with its conducting segment, and, since grid 52 is now positiveand grid 44 negative .with respect to cathode, current flows from theterminal 34-01 the'power supply to anode-cathode circuit of' device 61,conductor 66 contacts'Cl, brush BI, vone of, thesegments Ila-lid,conducting ring ll, brush BCl'anode 58 and related cathode, to conductor41 and terminal 48 of-the said power supply, thereby rendering thedevice 8 1 conductwo, during this said halt cycle, which is indicated atC ,in Fig.6, to transmit-the first signal of the combination; Also,duringthis halt cycle,

.contact is made with brush B2,- however, since contacts'C! are open,and since grid 44 "is non tive,'.at this time, the circuitconnected toanode5'lis maintained non-conducting.

.During the third cycle of operation otdevice distributing means. .50

. is indicated at A in Fig.

the latter, even though contacts C4 are closed,.

due to the negative grid 44,'and wlthcontacts C3 open, a circuitcannotbe completed through.

brush 33. Thus, no signal is impressed on the transmission medium, atthis time, in the'sig naling cycle,-as indicated at E in Fig. 6. Duringthe fifth cycle of operation'oi device Tl, brush B4 remains in contactwith-conducting ring I l, and since contacts 04 are closed, and the grid44 is, positive, at this time, a circuit is completed'to; render theoscillator device 61 conductive, as indicated at Fin Fig. .6..- Contactis broken with brush B3 and made with B5, -how-- ever, current cannotnow through the latter due to grid 52 being negative.

,During thefsixth cycle at operation'of device Tl, current is permittedto flow through brush B5, due tothe positive grid 52, thereby rendering.theoscillator device 51 conductive, at this time,

as indicated at Gtin Fig. 6.

,During theseventh cycle of operation of device'I'l, grid52 becomesnegative to render device 61 non-conductive.

brush -BP, but, due to the condition of grid 52,

no currentcan flow through this circuit at this Grid 44 is positive, butno current can' now through brush B5, since contacts C6 are open. Thiscondition is indicated at H in Fig. 6. During the eighth cycle ofoperation of device Tl, contact is made with brush BS to render theoscillator device Tl conductive continuously. Current also flows throughthe brush BP, since. grid 52' is nowDOsitive with respect tocathode,

generatethe continuous signal condition, which the absenceofcharacterfsignals. This condition permutation signals are initiatedand transmitted, during a signaling cycle, by means of "the novelReceiving-circuit arrangement I Reterring again-to Fig, 1, the receivingcircuit connections, shown in the lower half section of the figure, aresimilar to those of the transmitting circuit, just described. Theimpulse distributing means, at both transmitting and. receivingstations, are identical instructure and operation, 7

as well as the control circuits associated with the devicesTl, T2 andT8. 'acters are used todenote like elements and circuits. .For thisreason, itis not deemed necessary to-repeat the detailed description ofthe opera-- tion 01' these like elements 7 and circuits. Control magnetsMl-Ml ingtelegraph receiving unit, indicated generally by the referencecharacter lib-are connected to cathodeanode circuit or electrondischarge device l2, and by means or conductor 83 are conresistor SI. Itis well known,ho'w the control magnets Ml-Mi nected to brush Bs throughthe are en'ective' to control the for eii'ecting the selection of theContact is made with 51 conductive to 6-. In this manner, the 1 'Similarreference charof a suitable printcharacter type elements, in accordancewith the character code signals received.

In the present system, an additional control magnet MP, for controllingthe printing operations, is employed. The specific control function thismagnet will be described later. It will sufllce to say, for the present,that this control magnet is energized upon receipt oi the permutationcode signals to effect the printing operations. One terminal oi the saidmagnet is connected to brush BP, and the other terminal is connected byconductor 83 to terminal 8! of the power sup- The terminal apparatus forreceiving the signals is shown to comprise a full wave rectifierdischarge device 85, the separate anodes oiwhich are connected to theterminals of the secondary winding of the transformer as, the primarywinding of which is connected to the terminals all, and shunted by a;signal amplitude limiting resister 88. A center tap connection isprovided from the secondary winding to one terminal or resistor 89, theother terminal of which is connected to the cathode of device 85, andgrid element of device 82. Biasing potential is supplied by battery 90,and impressed upon the grid of device 82 to render the latternon-conductive, when no signals are received.

Assume now, that the continuous signal represented by A in Fig. 6 isimpressed upon the terminals Bi and device 8b. The signal oscilla= tionsare rectified by device 85, which in turn, impresses a continuous DCrectified voltage across resistor 89, which DC potential is oi suchvalue, as to overcome the biasing potential impressed upon the grid ofdevice 32, thereby renderingthe latter conductive. A circuit can then betraced from terminal 3d of the power supply, anode-,

cathode of device 02. conductor 8i, resistor to, brush BS, conductingsegment 82b and related conducting rings l2 and it, brush Bcl, conductor34, grids 36 and 52 of devices Ti and T3, re-

spectively, resistor 38, winding 31, conductor 38.

resistor St to terminal 48 of the said power supply. Thus, as describedhereinabove in connection with the transmitting circuit, the biasingpotentials impressed on said grids are overcome or neutralized, so thatthe related triode sections are rendered conductive continuously.-Another control circuit can be traced from terminal 36 of the powersupply to conductor 8%, magnet MP, brush BP, conducting segment Ho andring ll, anode 58 and related cathode, to conductor 41 and terminal Q8of the said power supply; thus-energizing the said magnet, whenever theimpulse distributing means is in the home position indicated, and asignal is impressed upon the said signal receiving means.

In order to-simpliiy the description to follow, it will be assumed, thatthe described signal combination initiated by the operation of contactsCi, Cl and C6 is impressed upon the signal receiving means; The firstsignal of the combination is the start signal condition, represented atB in Fig. 6, by having no signal oscillations impressed upon thereceiving means. As

mentioned, tor-this condition, no potential is impressed across resistor89, and consequently device I! is rendered non-conductive, therebyremoving the neutralizing potential impressed upon grids liandii. DeviceTl now is'condie,eee,ees'

to anode 58 also becomes non-conducting, due to the said conditioning ofgrid 52, thereby efiecting thedeenergization of the print magnet MP. Thefrequency of the oscillatory means at the receiver is adjusted, so as toapproximately be the same as that of the transmitter, and under "theseconditions, it has-been found, that the two impulse distributing meanswill operate in synchronisrm During the second stepping operation of thedisbuting means, the first signal of the comlotion is' received toestablish the following circuit: From terminal ct oi the power supply tothe anode-cathode elements oi device 132, conductor ti, control magnetMi, brush Bi, conducting segment lib and ring it, brush B025, anode 5tand related cathode, to conductor 51 and terminal it of the said powersupply, enersaid magnet.

During the third and fourth stepping operations of the distributingmeans, no circuits are established, due to the absence of controlsignals. But, during the fifth stepping operation,

a circuit is established from terminal as of the h power supply toanode-cathode elements of device 82, conductor 8!, magnet MG, brush B 3,conducting segment mo and ring it, brush B02,

anode 5i and related cathode to conductor" 41 and terminal as of thepower supply, energizir'n; said magnet. During the sixth steppingoperation, a circuit is established to magnet M8, through brushes B5 andBC% to anode 28, to effect energization of this magnet. During theseventh stepping operation no signals are received, 'and during theeighth and last stepping operation in this signaling cycle, theconducting rings are positioned to a home position to effect energize.-tion of the print magnet IVE, through the'circuit traced hereinabov'e,thereby completing the cycle of operations.

Upon energization or the print magnet, the character is printed inaccordance with the selection effected by the energization of the saidcontrol magnets. One emboent of a receiving teleprinter, utilizing aprint magnet as referred to, will now be described.

Receiving teleprinter unit- Patent No. 2,165,247. To overcome thiscondition, A

certain modifications of the structural details of this unit have beensuggested, whereby the received signals are stored by the control clutchunits associated with the permutation bars. Upon receipt of the signalsof each combination, the print control magnet is energized to effect theselection of the character type elements and recordingof'the'characters. With reference now to Figs. 7-9, the changes referredto will be described.

The rotatable permutation bars Hill, of which six are shown, areprovided with individual clutch units, comprising annular member I01,secured to'a related bar, which member is shaped tioned to function asan oscillator, and efiective The described circuitconnected to receive amovable dog 102; The said dog is provided with .a single :tooth I03normally-held out of engagement withthe associated ratchet wheel I'M. 'Apivoted dog lift lever I05 is pro-' vided to control the positioning ofthe dog. and

normally is engaged by clutch stop arm I08 aehired" to. armature inf-e:magnet iul, which a 1 one of the control magnets M.I-- M6 referred to."

'aasaaos It is described in detail in Patent No. 2,165,247, I I

how the" main drive gears, one of which isindicated by-the referencecharacter I08, are driven. to effectcontinuous rotation of theindividual gears I05, and the relatedstud shafts .I I0, which nals ofthe permutation shafts in'turn cause the rotation of the associatedratchet wheels in. 1

Referring now to the dog liftlever I (see Fig.

' 9a) it is-noted, that two individual stops III and II! are' fQrmedthereon and arranged one below the other inoffset positions with-respectto each other. The upright section of the cooperatingstop arm I05 isprovided with a ti-shaped slot H3 in one side thereof, sothat theuppermost section I I0 of the stop arm can engage the upper stop. III ofthe dog lift lever I 05, whenever the armature I0! is in a releasedposltionas shown. In this manner, the dog I02 is. held in a position,

so that its tooth is prevented from engaging the v associatedrotatingwheel, and consequently, preventing the associated permutationbar from be- 'ing rotated or operated.

Now, upon ener'gizationflof the related control magnet, for examplemagnet MI, the stop arm I06, as viewed in Fig- 9, ispartially rotated'ina,

clockwise direction, thereby resulting in the disengagement ofthe stopsection Ill and upper 1 stop III of the dog lift lever, and theengagement ing means .associated therewith are similar in structure andoperation as those described in Similar reference charofthe said stopsection with the lower stop II2 of the dog lift lever. This resultantaction is quite similar to actions ofwell known escapeinent mechanisms.The escapem'ent action is positive,

.due to the'fact that the dog m n constantly urged, by spring means (notshown in the present application but described'in detail in thePate'nt2,165,247), in the direction of the ratchet wheel.

The stop arm I06 is retained in the shifted position, by' means of africtional lock, comprising'the spring urged ball II6 engaging theuppermost notch- II6 formed in the .side opposite the one with'the slotII3 of the upright section of stop arm. 1

It is evident now, that, as the control signals K are impressedr uponthe individual magnets MI-M6 to effect energizationithereof, the saidsignals are effective to cause the controlled clutch units to be shiftedas-described, and store the,

" corresponding signals until the clutch units are released completelyto effect rotation of the -re-' -1ated permutation bars.

. The release of eachclutch unit is under control of the print magnetsMP, only one-of which is shown, however it will be understood, that oneprint magnet is provided for each group of three control magnetsincluded in the printer unit.

The saidlprint magnet is mounted below; the 'rer lated group of controlmagnets, and is provided with a pivoted armature H1 to which anextension arm IIB'is secured, there, being an extension arm for eachrelated control magnet. The said placed or shifted stop arms I06, uponenergization of the print magnet MP; to restore the said extension armsare adapted to engagejthe distion II- I ef'the restored stop arm, toeffect engagement -of thesaid dog tooth. and ratchet.

' repeated here.

contacts SI-SB. "the send position the normal position.

dis-

Thus, it is seen, that all theshiftedclutch units are released, uponenergization of the associated print magnet MP, to effect rotation ofthe related permutation bars, after the different sigcombinations arereceived and stored.

Each permutation bar we is provided with a plurality of diametricallyopposed slots II9-, which bars up'o'n rotation, in permutative groups,

present-certain of the said slots under the controllevers I20, so thatone control lever 'isse-- lect'd and permitted to drop in the channelprovided by those slots which are in alignment. The

selected control lever is then effectiveto operate its attached key barlever- (not shown) to cause the character tobe recorded, in accordancewith the code signals impressed upon the controhmag- 20- I nets .MI-MS.

Two way operation 7 Referringnow to Fig 10, the description of thepreferred embodiment ofa two way system will be given. Thesingle'impulse distributing means, oscillatory control means, andimpulse generatconnection with Fig. 1. actors are used to denote likeelements and circuits, and'therefore this description will not .be

To simplify the following, the description will be limited to. thecontrol elements and circuits of one station, it being understood-thatany numsequentlytransniitted over the associated trans- -.mission mediumby the means, described in detail hereinabove, and in signaltransmitting dicated S'I'M in Fig. 10. I

A plurality of signal storage relays RI B,6 are provided, v theenergization of whichare con-. gtrolled .by the contacts CI+C6 withtheswitch 3 S in the send position. Each of the said relays havesingietransfer contacts designated RBI-RC6. In the normal said contactsconnect the magnets MI--M6 to the distributor brushes BI-B6. Uponenergizetion of the relays, the transferred contacts RCI -RC6 areconnected to the said brushes BI-BS to control'the transmitting means"STM upon operation of the distributor, in accordance with the operatedcontacts CI-CG;

elements indicated I50 and I5I arms to the normal position shown. Uponres-v Y 1 ,toration of a stop arm I06, the uppermost sec tion Illthereofis disengaged from the lower stopIIZ, thereby releasing the doglift lever I05 and permitting the tooth or the dog I02 to engage therelated ratchet wheel. This operation results in the rotation of theassociated permutaof a revolution of the tion bar. Upon'completion barand clutch unit, the upper stop III of the dog lift lever again engagesthe uppermost sec-.

connected to each relay coil.

.these elements is to prolongselectively the ener- It'is seen, thatindividual resistor-capacitor respectively, are The purpose, of

,gization of the associated relays, thus insuring conducting rings I0and II.

and with the contacts CI- -C6,

that the different contacts ROI-RC6 remain closed at the timestherelated brushes BI-BGI are engaged by the segments of the respectiveNow, with the switch s in the send and- Cs in the position shown, the

position,

Eli

positions shown, a circuit can be traced from terminal 34 of the powersupply to conductors l3 and I52, normally closedcontacts S2, CS, and SI,conductor I53, resistor 60, brush BS, one of the segments of conductingring I2, conducting ring I3, brush BCI, conductors 54, 53, resistor 36,secondary winding 31, conductor 39, terminal 40 to resistor GI andterminal 48 of said supply. It is recalled that, by means of the circuittraced, the biasing potentials impressed on grids 35 and 52 areneutralized to "render the device TI, and the triode section of deviceT3 controlled by grid 52, conductive, as long as the contacts CS remainclosed.

Another circuit can be traced at this time from said terminal 3 3,conductors 33 and I52, normally closed contacts S2, signal transmittingmeans STM, conductor Itid, brushBP, one of the segments of conductingring II, brush B03 anode 5B and related cathode, and conductor 41 toterminal 48 of the power supply. In this manner the signaltransmitting'means STM is effective, as described hereinabove, to.impress the continuous signal condition, indicated A in Fig. 6, on theassociated transmission medium.

Upon selective operation of the contacts CI--C5, and CS, and to continuewith.the chosen example, assume contacts CI, C4, and C5 are operated,the relays RI RA, and R5 are energized. One of the circuits foreffecting such energization can be traced as follows: Terminal 3d of thepower supply, conductors 33 and I52, normally closed contacts S2, one ofthe said-contacts CI, coil of relay RI and associated resistor-capacitornetwork, conductors I55 and 39, terminal 40, and resistor 6i to terminal48 of the said supply. Upon energization of the relays RI, R6, and R5,the related contacts RC5, RC4, and RC5 are transferred.

Also, upon operation of the contacts CI, Cd, and C, contacts CS areopened m ientarily to open the circuit traced, to permit the biasingpotential impressed upon grids 35' and 52 to be effective to render thecontrolled triodes substantially non-conductive. It is understood fromthe description given, that under these conditions, the device Ti is nowadapted to function as an oscillator to control the conductivity of thetriode sections controlled by grids 43, 49, 44, and 52 of devices T2 andT3, respectively.

Magnets 25 and 28 are now energized, alternately, for.the duration of 'asignaling cycle, to advance the distributor means eight steps. Due tothe transferred contacts RCI, RC4, and RC5, the transmitting means STMis'controlled by the control circuits interconnecting the said contactsand brushes BI, B4, and 35, as the said circuits are made available,upon advancement of the conducting rings, under control of the deviceT3. The code group of signals generated by these circuits, for thechosen example, are shown in Fig. 6.

ployed. However, once the frequency rate is determined, and condenserTVC is adjusted accordlngly. it is desired for most conditions tomaintain this frequency rate for transmitting purposes. It is seen uponsetting of switch 8 in the receive position that contacts S3 are openedand the said condenser is isolated from the oscillator control circuits.

Now, assume that the described station is conditioned for receivingpurposes by placing the i switch 5 in the receive position. Thetransferred contacts S3 now connect the condenser RVC in the oscillatorcontrol circuits. This condenser is adjusted to, control the oscillatorTI so that its oscillation frequency rate is substantially equal to, orpreferably slightly greater than the frequency rate of the oscillator atthe remotely situated station which is transmitting to the presentstation conditioned as a receiver.

indicated A in Fig. 6 is impressed upon the'signal receiving meansdesignated SRM and described in detail in connection with Fig. 1. Uponreceipt of this signal, two control circuits are conditioned to maintainthe oscillator device Ti in a non-oscillatory condition, and to energizethe print magnet MP, respectively. The

first circuit can km traced from terminal 3 3 of' the power supply toconductors 33 and I52, transferred contacts S2, signal receiving meansSRM, conductor B56, brush BS, one of the conducting segments of ring it,conducting ring I3, brush BCl, conductors 5d and 53, resistor 38,winding, 31, conductor 39 to terminal 42, resistor Stand terminal it ofthe said power supply. This circuit just traced maintains the device TIcontinuously conductive, as well as the triode section controlled bygrid 52, for the reasons mentioned hereinbefore. The second circuitreferred to can be traced from terminal d3 of the power supply to thecathodeeanode of the triode section of device T3 controlled by grid 52,brush B03, conducting ring ii and one of its Upon the completion ofeight steps of the distributing means, the described circuits arerestored to the normal conditions just mentioned and described in detailhereinabove in connection with Fig. 1. a I

It is to be noted I that the normally closed contacts S3 connect thevariable condenser PVC in parallel circuit association with condenser 45and secondary winding 31. The condenser TVC is adjusted to control thefrequency rate of the oscillations generated under control of device TI.The particular operating circumstances are determinate of thepredetermined rate to be emsegments. brush BP, conductor I54,transferred contacts S4, magnet MP to transferred contacts 82, andconductor it? to the terminal 34 of the power supply.

Now, upon receipt of the start signal, the neutralizing potential nolonger is impressed upon resistor 38, so that the device TI can nowfunction as an oscillator. energized alternately to advance theconducting rings eight steps. Upon receipt of the code groups of signalsmagnets Mi, M4, and M5 are energized in the manner described hereinaboveOne of these circuits can be traced from terminal 24 of the power supplyto conductors 33 and I52, transferred contacts S2, signal receivingmeans SRM, transferred contacts S5 and S5, magnet Ml, for example,normally closed contacts RC I, brush BI,

conducting segment of ring II, brush BC3,.anode 58 and relatedcathode-to terminal 48 of the said power supply. In this manner the saidmagnets are energized to store the signals in the clutch unitsdescribed. Upon completion of the eight Magnets 25 and 28 aresteps, thedistributing means establishes the described circuit to the printcontrol magnet MP which is energized to efiect recording of the selectedcharacter in accordance with the received signals. Upon receipt of thecontinuous signal condition A'in Fig. 6, the receiving circuits arerestored to the conditions described in detail hereinabove.

It should be mentioned that the signal distributing means and associatedcontrol circuits are claimed in a copending application Serial No.370,675, filed Dec. 18, 1940, the distributor means per se in copendingapplication Serial No. 370,676, filed Dec. 18, 1940, and the characterrecording device including the signal storage means in in saidgenerating means, for controlling the fre quency rates of the generatedoscillations, one of copending application Serial No. 370,677, filedDec. 18, 1940.

While there has been shown and described and pointed out the fundamentalnovel features,

of the invention as applied to a single modificae tion, it will beunderstood that various omissions and substitutions and changes in theform and details of the device illustrated and in its opera-.

tion may be made by those skilled in the art without departing from thespirit of the invention.

It is the intention therefore to be limited only as indicated bythe-scope of the followingclaims. What is claimed is: r 1. In a printingtelegraph system, a station adapted for transmitting and receiving codegroups ofsignals, comprising, in combination, distributor means andactuating control means therefor, means for generating oscillations,

start-stop means for rendering the latter efiective. for controlling theoperation of the actuating control means for the duration of a signalingcycle, a plurality of adjustable means, included A v the adjustablemeans havingmeans whereby it is capable of being set for a predeterminedfrequencyrate for the transmission of signals, and another of saidadjustable means having ,means whereby the latter is capable of beingset fora difierent frequency rate for receiving signals, a series ofsignaling channels, said distributor means having means for making thechannels available successively during the said signaling cycle at apredetermined rate, upon operation of the start-stop means, meansincluding said channels for initiating or receiving the code groupsofsignals, and settable means, in one status, for

conditioning the initiating means and the first mentioned adjustablemeans to be effective to control the distributor means for initiatingpredetermined code groups of signals at a predetermined rate over saidsignaling channels duringa signaling cycle, and, in another status, forconditioning the receiving means and second mentioned adjustable meanswhereby the latter is effective to control the operation of thedistributor means at a rate commensurate with its setting in order toinfluence the signaling channel s and receiving means in synchronismwith the received code groups of signals.

2. The invention set forth in the preceding claim characterized by thefact that the said adjustable means comprise variable capacitance means.

v l 3. The invention set forth in claim 1 wherein

